Field of the Invention
The present invention is in the general field of the mechanical processing of granular solids, and more specifically is concerned with an apparatus and a method for compacting granular solids through the application of both shear and direct compression forces.
Bulk granular solids are normally composed of particles of various irregular shapes and sizes. The compaction of such a heterogeneous mixture generally requires not only the rearrangement of particles, but the degrading of some of the particles to create fines to fit between the larger particles.
This degrading and rearrangement is most easily accomplished when the compaction process and apparatus encourages interparticle motion. Unfortunately, the application of the large solids contact stress usually necessary for compaction is most easily accomplished by direct compression without inducing interparticle motion.
In direct compression, the bulk granular solid is typically placed in a closed cylinder, and a force is applied to the material by means of a piston. The material is subjected only to a unidirectional compressive force, and this results in the creation of relatively few fines, and does not result in as great a degree of rearrangement as might be desired.